This invention relates to building construction in general, and specifically to an improved method of connecting two structural members which are part of a system for improving a building's response to lateral forces.
The purpose of a continuity system is to provide an engineered structural mechanism that transfers lateral loads across the building, typically through a roof or floor diaphragm. A continuity system generally consists of a plurality of spaced continuity lines that extend completely across both the length and width of a building. High winds and earthquakes are the two most common means of generating lateral forces in a building. In tilt-up buildings made with concrete wall panels, the lateral forces generated by the motion of the heavy walls during an earthquake creates very severe lateral loads on the structure.
Continuity ties can be separate members which are used to improve the connection between existing members of the structure to create a continuity system. In buildings with diaphragm roofs or floors, continuity systems often incorporate otherwise required structural members such as purlins or beams of the roof or floor into the continuity lines. Specially designed continuity ties are used to interconnect these otherwise required members. The present invention deals with such continuity ties.
Brackets called holdowns in combination with threaded rods have long been used in the industry as continuity ties. U.S. Pat. No. 5,249,404, granted to Alfred D. Commins and William F. Leek teaches using a pair of holdowns as part of a continuity tie. See U.S. Pat. No. 5,249,404, column 7, line 9. More recent examples of such brackets include U.S. Pat. Nos. 5,813,181 and 5,921,042, granted to Roger Wall Ashton, Robert Donald Lucey and John Duncan Pryor.
The above-mentioned patents are similar in how they form the particular continuity tie connection. A pair of aligned purlins to be connected are identified. Generally, the purlins will abut opposed sides of a beam. A first bracket is attached to a side of one of the purlins, and a second bracket is attached to the other purlin in alignment with the first bracket. A tunnel is then drilled through the beam in alignment with the brackets, and a bolt is run through the bore in the beam and attached to the two brackets by means of nuts, forming the connection between the two purlins. Depending on how the brackets are arranged and/or formed, these connections can resist both tension and compression forces.
The device of the present invention improves upon the connection made by the brackets of the prior art with a simpler design that is easier to install. Specifically, the device of the present invention does not require additional installation steps beyond those required to make a tension connection to also provide compression resistance.